1. Field of the Invention
This invention relates to well tools, and more particularly to electrical connectors for connecting electrical cables to electrically powered tools even when submerged in electrically conductive liquids.
2. Description of Related Art
For several years, wet connectors have been known for making electrical connections under water or in similar hostile environments in order to supply power to electrically operated devices, or to obtain data gathered by downhole instruments such as transducers for sensing pressures or temperatures. Some such wet connectors are for use in wells, such as oil and gas wells, where conductive liquids, such as salt water or water laden with conductive substances, are usually present.
Applicants are familiar with the following prior U.S. patents which are believed to be pertinent to the invention claimed in the present application for patent: U.S. Pat. Nos. 3,939,705, 4,105,279, 4,442,893, 4,500,156, 4,510,797, 4,553,428, 4,583,592, 4,624,309, 4,667,736, 4,722,393, 4,757,859.
U.S. Pat. No. 3,939,705, issued to Bernard J. P. Glotin, et al., on Feb. 24, 1976 and, a division thereof, U.S. Pat. No. 4,105,279 issued to the same inventive entity on Aug. 8, 1978, disclose a side pocket mandrel having a male electrical connector projecting upwardly from the bottom of the offset landing receptacle. This male connector has its lower end projecting through the wall of the mandrel where it is connected to an electrical conductor running upward alongside the tubing to the surface. An electrically powered measuring instrument having a wet connector on its lower end and a latch on its upper end is installable in the offset receptacle with its wet commentor engaged with the male connector and its latch engaged in the latch recess at the upper end of the receptacle. The wet connector may contain an insulating fluid such as liquid silicone. The electric cable serves to supply power to the instrument from the surface and to transmit data from the instrument to the surface.
U.S. Pat. No. 4,510,797 which issued to Shelby L. Guidry, et al., on Apr. 16, 1985 teaches use of a full-bore drill stem test tool having one or more recording gauges for storing data gathered by one or more transducers which may sense pressures and temperatures above a downhole valve. The test tool includes a section having electrical contact pins which are located at the upper end of internal longitudinal grooves. Orienting guides are associated with the grooves while an abrupt upwardly facing shoulder is provided a short distance below the grooves. A contact tool lowerable into the well on an electric cable has means for engaging the abrupt shoulder and when weight is set down, contact arms pivot from a retracted position to a position in which they extend outwardly and upwardly. As this contact tool is subsequently lifted the contact arms are directed by the guides into the grooves. The outer ends of the contact arms travel upward in the grooves and make electrical contact with the downwardly extending contact pins. Thus engaged, data stored in the recording gauges can be transmitted to the surface for read out and the data sensed by the gauges can be displayed at the surface as they are gathered so long as the electric cable remains tensioned sufficient to maintain the electrical connection between the contact arms and the contact pins. Lowering the contact arms only a very short distance will break the electrical continuity. Setting down weight causes the contact arms to be retracted so that the tool can be lifted back to the surface.
U.S. Pat. No. 4,553,428 issued to James M. Upchurch on Nov. 19, 1985. This patent discloses use of drill stem test equipment which utilizes the invention of Guidry, et al., U.S. Pat. No. 4,510,797 in such way that pressures below or above the test valve and pressures in the annulus exterior of the test tool are sensed. A contact tool can be run into the well as taught by Guidry, et al. to transmit the recorded data to the surface and/or for transmitting such data as they are sensed, these data in either case being handled by surface readout equipment.
U.S. Pat. No. 4,589,717 which issued to Alain P. Pottier, et al. on May 20, 1986 teaches a wet connector wherein the male connector is lowered into a well and is engaged with a female connector. The female connector contains a dielectric liquid and is meant to operate more than just once. The wet connector has several contact members on each of the male and female portions and is intended for use with a well logging tool.
U.S. Pat. No. 4,624,309 issued to Mark A. Schnatzmeyer on Nov. 25, 1986 and discloses an improvement over the inventions of Glotin, et al. of U.S. Pat. Nos. 3,939,705 and 4,105,279. U.S. Pat. No. 4,624,309 teaches use of a side pocket mandrel having a longitudinal groove extending from the upper end of the offset receptacle to the upper end of the belly of the mandrel. A male connector projecting up from the bottom of the receptacle is engageable with a female wet connector on the lower end of a monitoring tool lowered into the well with an improved kickover tool attached to a slick wireline. The male connector has its lower end extending through the mandrel wall and connected to an electric conductor which extends to surface readout equipment at the surface. The female wet connector initially contains a non-conductive liquid which is displaced upon mating of the connectors in order to flush away and displace conductive substances from the male connector.
U.S. Pat. No. 4,757,859 also issued to Mark A. Schnatzmeyer on July 19, 1988 and is a continuation-in-part of his parent application Ser. No. 653,585) which matured into his U.S. Pat. No. 4,624,309 just discussed. Additionally, this U.S. Pat. No. 4,757,859 discloses an improvement in the female wet connector in that it is provided with reserve capacity for the non-conductive liquid. A floating piston separates the top of the non-conductive liquid from well fluids to which the upper side of the piston is exposed. Thus, although a certain amount of non-conductive liquid is lost upon mating of the connectors, enough non-conductive liquid can be carried for several connection operations.
U.S. Pat. No. 4,442,893 issued on Apr. 17, 1984 to Tommy C. Foust for an improved kickover tool for installing devices in and removing them from side pocket mandrels. The kickover tools disclosed in U.S. Pat. Nos. 4,624,309 and 4,757,859 of Mark A. Schnatzmeyer (supra) are improvements over that disclosed in this earlier patent of Tommy C. Foust. Each of the prior patents cited above is hereby incorporated into this application for all purposes, by reference thereto.
U.S. Pat. No. 4,583,592 issued to Imre I. Gazda on Apr. 22, 1986. This patent teaches use of a zig-zag slot/pin arrangement much like the pin/slot arrangement disclosed in the present application. Gazda's zig-zag slot 354 is shown in FIG. 8 of his patent and the pin 350 is shown to be carried on a floating ring 348 in FIG. 2B. The floating of ring 348 is necessary since the zig-zag slot 354 is formed on lower housing section 206 which, due to substantial preload on compression spring 220, would rotate only with great difficulty because of the great friction which would develop at the ends of the spring and at the o-rings.
There was not found in the known art a wet connector for releasably locking the lower end of an electrical cable to a remote electrically powered device for transmitting electrical power or signals therebetween.
The present invention is an improvement over the known wet connectors for running on an electric cable in that it enables mating of male and female connectors in a hostile environment, such as downhole in a well which may contain salt water and/or other conductive substances, and also to latch them together to permit tensioning of the electric cable and yet are readily releasable for ready withdrawal to the surface. The present invention is also directed to systems utilizing wet connectors for connecting an electric cable to remotely located electrically operated tools, such as downhole well tools, and wherein such wet connectors are releasably latched or locked in place.